Well, sort of. It isn't necessary, but if you're predicting intelligence from what someone does rather than direct measurements of physical properties, knowing their motivation level might allow you to make more accurate predictions.   Nevertheless even without knowing the subjects' motivations at all, today's generic intelligence tests still have excellent predictive power for success in both school and employment, and are perhaps better predictors for future success than any other method we have (including interviews, personality inventories, aptitude in a particular field)
Label: Non-Sarcastic